Layer 1 blockchain
ICON ticker ICX
Shutdown announced for Dec 31, 2026. It was still running at its last profile review; see the system note below.
Summary
ICON's docs describe delegated proof of stake. ICX holders stake and delegate to registered validators (P-Reps); the top-ranked validators take turns proposing a block, the others vote on it, and a block that passes is added to the chain, about every two seconds. In its open phase the 2022 docs put main validators at ranks 1 to 25, paid from 3 million newly minted ICX a month and backed by a bond. The Foundation's 2026 wind-down removed the bond, ended emissions on 26 March 2026 and cut consensus to seven core nodes. A read of the chain's system contract on 29 September 2026 listed the seven main P-Reps as five nodes named ICON Foundation, PARAMETA and sudoblock; the Foundation-named nodes held about 72% of their delegated weight. The Foundation says it controls the network during the migration, and it halted the chain for about 25 hours in August 2026. 111121319212326
Design
- System
- Layer 1 blockchainICON is a delegated proof-of-stake layer 1 (mainnet network ID 0x1, node software goloop) in a planned wind-down run by the ICON Foundation. Emissions and staking rewards ended on 26 March 2026, consensus was cut to seven core nodes, and ICX now converts one way to SODA, a token on Sonic. Blocks and transactions were still being processed on 29 September 2026, so it is profiled as a live layer 1; the Foundation plans a permanent halt on 31 December 2026 with a read-only archive, after which it should be reclassified as a chain that no longer runs and described as history.
- Settlement family
- Its own design
- Scarce resource
- Stake (proof of stake)
- State model
- Accounts
- Finality
- Other
- Who makes blocks
- Main P-Reps take turns proposing blocks in rounds; if a block is voted invalid, another validator is chosen, per ICON's docs. Registering as a validator cost 2,000 ICX. For the wind-down the Foundation added four nodes and moved its delegations so that seven core nodes hold ranks 1 to 7, and nodes ranked eighth and below were excluded from block production and consensus. The Foundation calls all seven Foundation-controlled, while the chain's registry names two of them PARAMETA and sudoblock, and none of the seven held a bond on 29 September 2026; who operates each node was not verified.
- Fork choice
- No open weight-based chain selection: a block joins the chain only after the other validators vote it valid, and ICON's learning pages describe its two-second blocks as final. The vote threshold and fork handling could not be checked in the node code, because the goloop repository linked from the docs returned not found on 29 September 2026. In practice the Foundation can stop block production: it halted the chain at block 117,479,936 on 27 August 2026 and restarted it about 25 hours later, saying balances were unchanged.
Qualifications
- Operating status · Partial. Live but winding down. Node reads on 29 September 2026 returned block 118,882,819 at 17:13 UTC and block 118,883,791 at 17:45 UTC, about two seconds per block. The Foundation calls this maintenance mode: no emissions or staking rewards, seven core nodes, two-way ICX and SODA conversion closed on 25 September 2026, and a planned permanent halt on 31 December 2026 with a read-only archive afterwards.
- Steward control · Partial. The Foundation's post-mortem says the network is controlled by the ICON Foundation during the token migration period. It paused its migration contract and then halted the whole chain from 06:18:54 UTC on 27 August 2026 to about 07:51 UTC on 28 August, deployed a fix during the restart and added an allowlist so only its own relayer can submit withdrawal messages.
- Slashing · Contested. ICON's 2022 governance page says a validator's bonded ICX can be slashed for unstable block production or malicious activity, and proposal types include slashing rates. The current rewards page says penalties are turned off on mainnet, and the 2026 wind-down removed the bond requirement, so no stake is known to be at risk for the seven core nodes.
- Scarce resource · Partial. Validators rank by the ICX delegated to them, which is why stake is recorded. For the wind-down the Foundation moved its delegations so that seven core nodes hold ranks 1 to 7; five are named ICON Foundation and hold about 72% of the delegated weight. None of the seven held a bond on 29 September 2026, emissions and staking rewards ended in March 2026 and penalties are switched off, so little economic value is at risk or earned by validating.
- Node software source · Unknown. ICON's docs link the goloop client's GitHub repository, which returned not found on 29 September 2026. The Go module mirror still lists tagged versions up to v1.4.4 (2 October 2024) and a v1.4.5 release candidate dated 22 July 2026; which version mainnet nodes run was not verified.
- Shutdown governance · Unknown. The Foundation's May 2026 post said a governance vote would ask validators to approve the shutdown on 31 December 2026. Whether that vote was held and its result were not verified. On 29 September 2026 five of the seven main P-Reps, holding about 72% of their delegated weight, were named ICON Foundation, above the 67% threshold ICON's 2022 governance page gives for network proposals.
- Throughput · Unknown. No classed transaction-rate figure from ICON was found in the reviewed sources, so no throughput claim is recorded. The two-second block interval is a timing observation, not a capacity figure.
- Settlement family · Partial. Recorded as other. ICON's own terms: an independent delegated proof-of-stake chain run by goloop, the client the ICON Foundation supports, with its own JSON-RPC v3 interface, hx user and cx contract addresses, Java smart contracts and fees measured in steps and paid in ICX.
- Finality · Partial. Recorded as other. ICON's own terms: validators take turns proposing a block and the other validators vote on whether it is valid; a block that passes is connected to the chain and its transactions are confirmed permanently, which ICON's learning pages describe as two-second blocks with finality. Penalties are switched off on mainnet, and since March 2026 seven core nodes cast every vote.
Tradeoffs
- Emphasizes
- Scalability Contested
- Gives up
- Decentralisation. In its open phase block production sat with a small elected committee (main validators ranked 1 to 25 in the 2022 docs), and since March 2026 seven core nodes, five of them named ICON Foundation, produce and vote on every block without rewards or a validator bond. The Foundation halted the chain for about 25 hours in August 2026 to contain an exploit and plans to end it on 31 December 2026, so users rely on one steward's decisions for liveness and for the chain's remaining lifetime.Scalability is listed because ICON's 2022 overview says its two-second blocks with finality let developers build responsive applications; no classed transaction-rate figure was found. The same overview says ICON's incentive system aims to maximize decentralization and stake, so reading scalability as the emphasis and decentralization as the cost is contested. No stake is known to be at risk today: the docs say validator penalties are turned off on mainnet, and the bond requirement was removed in 2026. The emphasis describes design goals, not the current outcome.
- Full node at home
- Demanding 7910181922ICON's validator and API-endpoint guides list the same minimum for both roles: 4 CPU cores, 16 GB of RAM, a 2.5 TB SSD and a 1 Gbps connection, with 8 cores, 32 GB, 3 TB and 2 Gbps recommended, running the iconloop/icon2-node Docker image. A new node can restore the latest snapshot database instead of replaying history, which means trusting that snapshot. Only the seven core nodes take part in consensus, and the Foundation plans to halt the chain on 31 December 2026, after which there is nothing new to follow.
- Throughput claims
- No classified figure recorded
Scaling layers
No scaling layer recorded in this profile.
Capabilities
| Capability | How it is provided | Notes and sources |
|---|---|---|
| Account abstraction | Structured assessment pending | Not yet assessed for any chain. |
| Atomic swaps | Unknown | No hash-time-locked or other trust-minimised swap mechanism settled on ICON was documented in the reviewed sources. Java smart contracts could host one, but none was reviewed. The ICX-to-SODA migration runs through the Foundation's migration contract and relayer, not a two-party swap. 623 |
| Authenticated data publication | Unknown | Not yet assessed under this row's current definition. |
| Light clients | Unknown | Building blocks only. The Blockchain Transmission Protocol was designed around on-chain verifier contracts that check another chain's blocks, but ICON's docs list those verifiers only on test networks and warn of outages, and no light client for checking ICON's own blocks was found. New nodes can restore a snapshot database instead of replaying history. 101215 |
| Native staking or delegation | Structured assessment pending | Not yet assessed for any chain. |
| On-chain governance | Structured assessment pending | Not yet assessed for any chain. |
| Parallel execution | Structured assessment pending | Not yet assessed for any chain. |
| Payment or state channels | Unknown | No payment or state channel layer anchored to ICON was found in the reviewed sources; absence was not verified. |
| Programmable spending | Native (protocol or core-team software) Earlier definition | User accounts (hx addresses) are controlled by keys; smart contracts (cx addresses) written in Java run in ICON's Java execution environment, with fees charged per instruction in steps. The earlier Python engine is deprecated. On mainnet, the Foundation's migration contract holds ICX and releases it under its code, as the August 2026 post-mortem describes. Contracts can execute only until the planned halt on 31 December 2026. 3562223 |
| Protocol-verified messaging | Structured assessment pending | Not yet assessed for any chain. |
| Reversible transfers or recovery | Unknown | Not yet assessed under this row's current definition. ICON's docs say a transaction in a confirmed block is recorded permanently; no sender reclaim window or pre-arranged recovery path was found in the reviewed sources. 4 |
| Rollups | Unknown | No rollup anchored to ICON was found in the reviewed sources; absence was not verified. ICON's cross-chain tools (BTP, xCall and ICON Bridge) connect separate chains and are not rollups. 1617 |
| Shielded transfers | Structured assessment pending | Not yet assessed for any chain. |
| Signed partial offers | Unknown | Not yet assessed under this row's current definition. |
Reading these values
- How this feature is provided
- Built into the protocol, core-team software or independent software says where a feature lives and who can change it. These are implementation layers, not quality: core-team software is not closer to the protocol than independent software.
- Structured assessment pending
- The shared review has not assessed this feature for any chain yet (Account abstraction, Native staking or delegation, On-chain governance, Parallel execution, Protocol-verified messaging and Shielded transfers). That does not mean it is absent, and a chain’s profile may already describe it.
- Unknown
- The review has not established this for this chain under the current definition; the note beside it says why. Unknown is not absent and not a low score. A feature reads “Not present” only when a source shows it is absent.
- Earlier definition
- Payment or state channels, Programmable spending and Rollups keep the earlier definition until the next fact-check. There, “Native” does not separate the protocol from core-team software, “Ecosystem software” does not say who publishes it, and “Partial” does not say which layer.
- Reading across rows
- The list of capabilities is incomplete. Do not read these rows as a chain leading or lagging overall.
Ecosystem & custody
| Product type | Status | Notes and sources |
|---|---|---|
| Automated market makers | ThinBalanced (exchange on ICON) | Balanced built an automated market-maker exchange on ICON, including sICX/ICX pools. The Foundation announced that Balanced's savings-rate rewards would end on 2 March 2026 and its ICX/sICX liquidity rewards on 13 March 2026, saying there would soon be no incentive to keep funds in legacy pools, and the Balanced site now describes cross-network swaps that use SODAX intents without mentioning ICON. DefiLlama's third-party index still listed Balanced Exchange with value locked on ICON on 29 September 2026; the depth of the remaining pools was not assessed. 12203031 |
| Issuer-native stablecoins | ThinbnUSD (Balanced Dollar, legacy ICON token) | Neither Circle's USDC list nor Tether's list of supported protocols includes ICON. bnUSD, the Balanced Dollar, was minted by Balanced's contracts on ICON against collateral; SODAX now offers a new bnUSD and converts the legacy ICON token to it. The August 2026 exploit released foundation-held bnUSD, which the Foundation says it fully recovered. How much legacy bnUSD remains on ICON was not measured. 2329303233 |
| Algorithmic stablecoins | Unknown | Balanced's own site describes bnUSD as backed by collateral, not an algorithm, and ICON's ICX learning page calls it a collateralized stablecoin, so it is listed once, with native stablecoins; ICON's 2022 overview page does call bnUSD an algorithmic stablecoin. No other algorithmic stablecoin on ICON was reviewed. 121430 |
| Bridges | First-partyICX and bnUSD migration contract to SODAX on Sonic (ICX to SODA one way since 25 September 2026), ICON Bridge (relay run by Parameta), xCall message passing (BTP and IBC) | The Foundation's migration contract converts ICX to SODA and legacy bnUSD to new bnUSD on Sonic, with withdrawals processed by the SODAX Asset Manager; since 25 September 2026 only the ICX-to-SODA direction is open, until 31 December 2026. ICON's docs describe ICON Bridge as a centralised token bridge to BNB Smart Chain whose relay Parameta runs privately, and xCall as ICON's message-passing interface over BTP and IBC. Whether ICON Bridge and BTP routes still carry mainnet traffic was not verified. Risk: On 27 August 2026 an attacker replayed two signed withdrawal messages 1,492 times through the migration and Asset Manager contracts, releasing 119,866,000 ICX and 531,600 bnUSD of foundation-held funds; the Foundation paused the contract, halted the chain and now accepts withdrawal messages only from its own allowlisted relayer. Users of these routes trust the Foundation's relayer and contract owners, and ICON Bridge users trust Parameta's relay. ICX not migrated by 31 December 2026 can no longer be converted. 161722232429 |
| Block explorers | ThinICON Tracker (tracker.icon.community, built by Sudoblock) | ICON's docs point to ICON Tracker, whose open repositories are kept by Sudoblock in its sb-icon GitHub organisation; sudoblock is also the registered name of one of the seven main P-Reps; Ledger's currency list also links to it. Its API answered on 29 September 2026. No second mainnet explorer was verified. Explorer data is indexed by its operator, not consensus, and the Foundation promises a read-only archive after the halt without naming its address. 82227283540 |
| Hardware wallets | ThinLedger (through Hana Wallet) | See the custody section: Ledger's ICON page routes users through Hana Wallet, Ledger Wallet's own ICON module sits behind a feature switch that is off by default, and Trezor says it does not support ICON. 343638 |
Hardware-wallet custody
| Device maker | Status | What users can and cannot do |
|---|---|---|
| Ledger | PartialHana Wallet, the third-party wallet Ledger's ICON page namesSame as native: Unknown | Can: Connect a Ledger device to Hana Wallet to send, receive and swap ICX, per Ledger's ICON page Can: Use the ICON device app that Ledger's currency list names for ICX, shown with 18 decimal places Cannot: Count on managing ICX in Ledger Wallet (formerly Ledger Live): its code carries an ICON module behind a feature switch that is off by default, and Ledger's ICON page sends users to Hana Wallet instead Cannot: Keep using ICX on ICON after 31 December 2026, when the Foundation plans to halt the chain; migrated SODA lives on SonicLedger's own wallet code includes ICON support but keeps it switched off by default; the same default-off setting covers many currencies that Ledger turns on remotely, so it does not by itself show that ICX is hidden. The ICON Foundation announced in September 2024 that Ledger Live could send and receive ICX and still recommended Hana for staking; whether Ledger has the switch turned on for users today could not be read, because Ledger's support article renders only in the browser. 22253435363739 |
| Trezor | None foundSame as native: No | Cannot: Manage ICX in Trezor Suite; Trezor's ICON page says Trezor does not currently support ICONTrezor's page asks users who used ICON with Trezor in the past to contact its support team. No route through a third-party wallet was reviewed. 38 |
Public data
iKnow Blockchain has no public-data lookups for ICON yet. This is a limit of the service, not a statement about the network.
| Lookup | Status | What it covers and its limits |
|---|---|---|
| Address or account | Not available yet | Public-data lookups for this chain are not built yet. |
| Tokens and assets | Not available yet | Public-data lookups for this chain are not built yet. |
| NFTs | Not available yet | Public-data lookups for this chain are not built yet. |
| Transactions | Not available yet | Public-data lookups for this chain are not built yet. |
Sourced developments
Developments: Reviewed Sep 29, 2026 Next review due Oct 9, 2026, 12:00 UTC.
Publication date · newest first
-
Two-way ICX and SODA migration closed on 25 September, five days early
The Foundation closed conversion from SODA back to ICX on 25 September 2026, five days before the date it had given, citing the share of ICX supply already moved into SODA, reduced support on centralised exchanges and lingering effects of the August exploit, and saying the early close limits the exposure of SODAX's infrastructure. One-way migration from ICX to SODA stays open until 31 December 2026, which the Foundation says will not move.
- Implementation:two-way conversion closed
- Release:announced 24 September 2026
- Activation:effective 25 September 2026; one-way migration open until 31 December 2026
Sources: ICON Foundation — ICX to SODA Migration Update: Two-Way Migration Closes Friday, September 25 (external site) · SODAX Documentation — SODAX SDK: Migration module (external site)
-
Migration-contract replay exploit led the Foundation to halt ICON for about 25 hours
On 27 August 2026 an attacker replayed two signed withdrawal messages 1,492 times through the ICON migration contract and SODAX Asset Manager, releasing 119,866,000 ICX and 531,600 bnUSD of foundation-held funds. The Foundation paused the contract, halted the chain at block 117,479,936, deployed a fix and a relayer allowlist, and restarted the chain on 28 August. It reports net confirmed losses of about 150.2 ETH and 31,204 USDC, with most ICX frozen at exchanges.
- Implementation:serialization fix and relayer allowlist deployed during the restart
- Release:post-mortem published
- Activation:chain resumed about 07:51 UTC on 28 August 2026; recovery of exchange-held funds ongoing
Source: ICON Foundation — ICON Network: Replay Exploit Post-Mortem (external site)
-
ICON Foundation set 31 December 2026 as the date to halt the ICON chain permanently
The Foundation announced that the ICON Network will shut down on 31 December 2026: the chain will be permanently halted, a read-only archive will be offered for historical lookups, and ICX can no longer be migrated after that date. It said a governance vote would ask validators to approve the shutdown in May 2026, and that migration would become one way from 30 September.
- Proposal:validator governance vote announced for May 2026; result not verified
- Implementation:not yet: blocks were still produced on 29 September 2026
- Release:shutdown date announced
- Activation:planned for 31 December 2026
Sources: ICON Foundation — Final Date Set for SODA Migration, ICON Network to Shut Down End of 2026 (external site) · ICON Foundation — ICX to SODA Migration Update: Two-Way Migration Closes Friday, September 25 (external site) · ICON public API endpoint (ctz.solidwallet.io) — ICON mainnet JSON-RPC: icx_getLastBlock (read 29 September 2026) (external site)
-
ICON entered economic shutdown: emissions and staking rewards ended
The Foundation said all staking rewards and ICX emissions had ended and that the network was in maintenance mode, with consensus handled by a reduced set of seven core nodes. It said the chain would stay live so holders could migrate ICX to SODA on Sonic, and that the bond removal lets validators unbond without penalty.
- Proposal:set out in the 6 February 2026 phased plan
- Implementation:emissions and rewards ended; validator set reduced to seven core nodes
- Release:announced by the Foundation
- Activation:in effect from 26 March 2026; seven main P-Reps observed on 29 September 2026
Sources: ICON Foundation — ICON Network: Economic Shutdown (external site) · ICON Foundation — ICON Network: Migration Roadmap and SODAX Reward Schedule (external site) · ICON community API endpoint (api.icon.community) — ICON mainnet JSON-RPC: getMainPReps on the system contract (read 29 September 2026) (external site)
-
ICON Foundation announced a phased halt to ICX emissions and a seven-node validator set
The Foundation set out five phases: a governance vote to remove the 1% validator bond (16 February), four added Foundation nodes (2 March), moving Foundation delegations so seven core nodes hold ranks 1 to 7 (16 March), excluding nodes ranked eighth and below from consensus (23 March), and an economic shutdown ending new ICX emissions (26 March). It said the chain would stay live for transactions and migration to SODA.
- Proposal:bond-removal governance vote announced for 16 February 2026
- Implementation:phased plan announced
- Release:Announced
- Activation:the Foundation's 26 March 2026 post says emissions ended and seven core nodes run consensus
Sources: ICON Foundation — ICON Network Phased Halt to Emissions (external site) · ICON Foundation — ICON Network: Economic Shutdown (external site)
Topics your AI can explain
Your AI can explain these topics for ICON through the connection, with sources.
Known gaps
What this profile's review did not establish:
- The goloop repository linked from ICON's docs returned not found on 29 September 2026, so the consensus rules, the vote threshold for a block and the version mainnet nodes run were not checked in code.
- The Foundation calls all seven core nodes Foundation-controlled, while the chain's registry names two of them PARAMETA and sudoblock; who operates each node was not verified.
- Whether the validator vote on the 31 December 2026 shutdown, announced for May 2026, was held and passed was not verified.
- The current step price, the step cost of a plain ICX transfer and where fees go after the economic shutdown were not read from the chain.
- Slashing is marked contested: the 2022 governance page describes slashable bonds, the rewards page says penalties are turned off on mainnet, and the bond requirement was removed in 2026.
- Whether Ledger has turned on Ledger Wallet's ICON switch for users could not be read; Ledger's ICON support article renders only in the browser.
- Which BTP, xCall and ICON Bridge routes still carry mainnet traffic, and whether Parameta still runs the ICON Bridge relay, were not verified.
- Remaining Balanced liquidity and legacy bnUSD supply on ICON were not measured.
- How much ICX has been migrated to SODA, and the recovery of exploited ICX held at exchanges, were not verified.
- No address, operator or format for the promised read-only archive has been published.
- ICON's validator guide lists a 2.5 TB SSD minimum while the icon2-docker README lists 1.5 TB; archive size was not measured.
- No classed throughput figure was found, and block timing comes from single reads on 29 September 2026.
- The current unstaking period for ICX after the 2026 changes was not verified.
- No atomic-swap tool, channel layer, rollup or recovery feature was found; absence was not exhaustively verified.
Sources
Oldest dated source check: Source checked Sep 29, 2026 Next check due Oct 29, 2026.
- Consensus mechanism (external site)
- Blocks (external site)
- Accounts (external site)
- Transactions (external site)
- STEP (external site)
- Java execution environment (external site)
- Goloop (external site)
- ICON Networks (API endpoints and tracker) (external site)
- How to run a Validator node (external site)
- How to run an API endpoint (external site)
- Rewards & Penalties (external site)
- What is ICON? (learning page dated 2022-03-07) (external site)
- What is ICON Governance? (learning page dated 2022-03-05) (external site)
- What is ICX? (learning page dated 2022-03-06) (external site)
- Blockchain Transmission Protocol (BTP) (external site)
- ICON Bridge (external site)
- What is ICON's General Message Passing (GMP)? (external site)
- Go module mirror: github.com/icon-project/goloop version list (external site)
- ICON Network Phased Halt to Emissions (6 February 2026) (external site)
- ICON Network Sunsets Balanced Incentives (23 February 2026) (external site)
- ICON Network: Economic Shutdown (26 March 2026) (external site)
- Final Date Set for SODA Migration, ICON Network to Shut Down End of 2026 (25 May 2026) (external site)
- ICON Network: Replay Exploit Post-Mortem (30 August 2026) (external site)
- ICX to SODA Migration Update: Two-Way Migration Closes Friday, September 25 (24 September 2026) (external site)
- Ledger Live Adds ICON Support (9 September 2024) (external site)
- ICON mainnet JSON-RPC: getMainPReps read on the system contract (29 September 2026) (external site)
- ICON Tracker API: latest transactions (read 29 September 2026) (external site)
- icon-tracker: meta repo for the ICON Blockchain's community tracker (external site)
- SODAX SDK: Migration module (ICX, bnUSD and BALN between ICON and the Sonic hub) (external site)
- Balanced (external site)
- Balanced Exchange protocol record (chains with value locked, read 29 September 2026) (external site)
- USDC contract addresses (external site)
- Supported protocols (external site)
- ICON wallet (external site)
- @ledgerhq/cryptoassets 13.56.0 currency list (ICON entry) (external site)
- @ledgerhq/live-common 36.0.0 default feature flags (currencyIcon off by default) (external site)
- ledger-live coin module loaders (icon family) (external site)
- ICON wallet (external site)
- Hana Wallet (external site)
- sb-icon: Sudoblock's contributions to the ICON blockchain (now SODAX) (external site)
Report an error
Found something wrong or out of date? Reporting is free, and every chain goes through the same process. Published corrections appear in the public log.
Funding disclosure
Funding disclosures appear here when an upkeep arrangement exists, in the form “Upkeep funded by [name]; verdicts unaffected.” The funder ledger has not been published yet. Neutrality & funding